Process for preparing 2-deroxy-3-desamino-2,3-epimino-aminoglycosides and intermediates useful therein

ABSTRACT

2&#39;&#39;&#39;&#39;-Deoxy-3&#39;&#39;&#39;&#39;-desamino-2&#39;&#39;&#39;&#39;,3&#39;&#39;&#39;&#39;-epimino-aminoglycosides useful as intermediates in preparing antibacterially active 2&#39;&#39;&#39;&#39;deoxyaminoglycosides, are prepared from antibacterially active aminoglycosides having a 2&#39;&#39;&#39;&#39;-hydroxyl group and a 3&#39;&#39;&#39;&#39;-primary or secondary amino function, by a process which comprises protecting primary amino groups and secondary amino groups capable of oxazolidine formation with an aldehyde and a neighboring hydroxyl group, by conversion thereof to Schiff base-oxazolidine condensation products with aldehydes (preferably benzaldehyde), converting any protectable primary and secondary hydroxyl groups to a trityl ether or to a cyclic ketal or acetal, treating said N-protected-O-protected-aminoglycoside with a hydrocarbonsulfonyl halide in a tertiary amine, treating the resulting N-protected-Oprotected-2&#39;&#39;&#39;&#39;-O-hydrocarbonsulfonylaminoglycoside (novel intermediates) with dilute aqueous acid to a pH in the range of from about 1 to about 5, and converting the resulting 2&#39;&#39;&#39;&#39;-Ohydrocarbonsulfonylaminoglycoside to a 2&#39;&#39;&#39;&#39;-deoxy-3&#39;&#39;&#39;&#39;-desamino2&#39;&#39;&#39;&#39;,3&#39;&#39;&#39;&#39;-epimino-aminoglycoside either by spontaneous transformation or heating in a lower alkanol alone or together with an alkali metal salt of said alkanol. The 2&#39;&#39;&#39;&#39;-deoxy-3&#39;&#39;&#39;&#39;desamino-2&#39;&#39;&#39;&#39;,3&#39;&#39;&#39;&#39;-epiminoaminoglycosides upon hydrogenation followed by acid hydrolysis of any ketal or acetal functions are converted to a product mixture comprising an antibacterially active 2&#39;&#39;&#39;&#39;-deoxyaminoglycoside isolatable via chromatographic techniques.

United States Patent [191 Daniels et al.

[ Feb. 25, 1975 PROCESS FOR PREPARING 2-DEROXY-3-DESAMINO-2,3-EPIMINO- AMINOGLYCOSIDES AND INTERMEDIATES USEFUL THEREIN [75] Inventors: Peter J. L. Daniels, Cedar Grove;

Jay Weinstein, Bloomfield, both of NJ.

[73] Assignee: Shering Corporation, Bloomfield,

[22] Filed: Oct. 24, 1972 [2]] Appl. No.: 299,983

[52] US. CL... 260/210 AB, 260/2l0 K, 260/210 R,

424/180 [51] Int. Cl. C07c 47/18 [58] Field of Search 260/210 AB, 210 R, 210 K [56] References Cited UNITED STATES PATENTS 3,268,508 8/1966 Sugazawa et al 260/210 K 3,651,042 3/1972 Marquez et al. 260/210 AB Primary ExaminerJohnnie R. Brown Attorney, Agent, or FirmMary S. King; Stephen B. Coan [57] ABSTRACT 2 "-Deoxy-3 "-desamino-2 ",3"-epiminoaminoglycosides useful as intermediates in preparing antibacterially active 2"-deoxyarninoglycosides, are

'preparedfrom antibacterially active aminoglycosides having a 2"-hydroxyl group and a 3"-primary or secondary amino function, by a process which comprises protecting primary amino groups and secondary amino groups capable of oxazolidine formation with an aldehyde and a neighboring hydroxyl group, by conversion thereof to Schiff base-oxazolidine condensation products with aldehydes (preferably benzaldehyde), converting any protectable primary and secondary hydroxyl groups to a trityl ether or to a cyclic ketal or acetal, treating said N-protected-O-protectedaminoglycoside with a hydrocarbonsulfonyl halide in a tertiary amine, treating the resulting N-protected-O- protected-2"-O-hydrocarbonsulfonylaminoglycoside (novel intermediates) with dilute aqueous acid to a pH in the range of from about 1 to about 5, and converting the resulting 2"-O-hydrocarbonsulfonylaminoglycoside to a 2"-deoxy-3"-desamino-2,3"-epiminoaminoglycoside either by spontaneous transformation or heating in a lower alkanol alone or together with an alkali metal salt of said alkanol. The 2"-deoxy-3"- desamino-2,3"-epiminoaminoglycosides upon hydrogenation followed by acid hydrolysis of any ketal or acetal functions are converted to a product mixture comprising an antibacterially active 2"- deoxyaminoglycoside isolatable via chromatographic techniques.

14 Claims, No Drawings PROCESS FOR PREPARING A-PEROXYV-Ve-DESA Q- a- IMW AMINOGLYCOSIDES AND INTERMEDIATES USEFUL THEREIN The epiminoaminoglycosides upon hydrogenation followed by acid hydrolysis of any ketal or acetal functions are converted to a product mixture comprising an antibacterially active 2"-deoxyaminoglycoside isolatable via chromatographic techniques.

FIELD OF INVENTION This invention relates to an improved process and to novel intermediates produced thereby.

More specifically, this invention relates to an improved process for the preparation of 2-deoxy-3"- desamino-Z",3"-epiminoaminoglycoside derivatives useful as intermediates in the preparation of antibacterially active 2"-deoxy-aminoglycosides, and to novel intermediates produced thereby.

DESCRIPTION OF THE PRIOR ART Novel 2"-deoxyaminoglycosides and 2"-epi-amino- 3"-desamino derivatives thereof, valuable as antibacterial agents, methods for their manufacture, and novel intermediates produced thereby, are described and claimed in co-pending application Ser. No. 300,083, filed concomitantly herewith of Peter J.L. Daniels for 2"-Deo.ryaminoglyc0sides and 2"-Epi-Amin0-3"- Desamino Derivatives Thereof, Methods for their Manufacture and Novel Intermediates Useful Therein. Among the antibacterial agents disclosed therein are 2"- deoxygentamicins and 2-deoxy derivatives of related aminoglycosides such as 2-deoxysisomicin, 2"-deoxytobramycin, 2"-deoxyverdamicin, 2",3',4'-

trideoxykanamycin B. 2"-deoxy-Antibiotic Jl-ZO-A,

2"-deoxy-Antibiotic JI-ZO-B, and 2"-deoxy-Antibiotic G-4l8, as well as the 2-epi-amino-3"-desamino or 2- -epi-methylamino-3"-desmethylamino analogs thereof. Among those disclosed as preferred compounds are 2-deoxygentamicin C 2"- deoxygentamicin C,a,2"-deoxygentamicin C 2"- deoxysisomicin and 2-deoxyverdamicin and nontoxic pharmaceutically acceptable acid addition salts thereof.

Described in said copending application is a method for preparing the 2"-deoxyaminoglycosides in admixture with the corresponding 3-desamino-2"-epiamino-derivatives which comprises treating an antibacterially active aminogycoside having a 2-hydroxyl group and a 3"-amino function, and having primary and secondary amino functions protected by carbobenzyloxy groups, and protectable primary and secondary hydroxyl groups converted to a triphenylmethyl ether or to a cyclic ketal or acetal derivative, with a hydrocarbonsulfonyl halide in pyridine; removing the carbobenayloxy groups in the thereby formed 2"-O- h ydrocarbonsulfonyl-per-N-carbobenzyloxy-O- protected-aminoglycoside by treatment with hydrogen in the presence of a catalyst or by cleavage with an alkali metal in liquid ammonia; converting the resulting 2"-O-hydrocarbonsulfonylaminoglycoside to the corresponding 2-deoxy-3"-desamino-2",3"-epimino intermediate by means selected from the group consisting of spontaneous formation, and heating at temperatures in the range of from about 25C to about 100C in a lower alkanol alone or in the presence of an alkali metal salt of a lower alkanol. The 2-deoxy-3"- desamino-2" ,3"-epimino-aminoglycoside intermediate thereby formed is then cleaved, followed by acid hydrolysis of any O-protecting groups which are presem to form a mixture of the corresponding antibacterially active 2"deoxy-aminoglycoside and the 3"- desamino- 2-epi-amino-analog thereof. It is disclosed that cleavage can be effected by hydrogenolysis in the presence of a catalyst or by N-derivatization of the 2"- deoxy-3"-desamino-2",3"-epimino-aminoglycoside intermediate optionally followed by quaternization of the epimino function with a benzyl halide and hydrogenolysis of the N-derivatized compound, or cleavage may be effected by treating the 2"-deoxy-3"- desamino-Z", 3"-epimino-aminoglycoside or N- protected derivative thereof with a sulfur nucleophile followed by desulfurization of the thio derivative thereby formed. Separation of the resulting product mixture may be carried out either before or after removal of any N-protecting groups which are present.

By our invention, we have discovered an improve ment in the foregoing process for preparing the 2"- deoxy-3-desamino-2",3"-epimino-aminoglycoside intermediates, which comprises protecting the primary amino groups and secondary amino groups capable of oxazolidine formation with an aldehyde and a neighboring hydroxyl group, by conversion thereof to Schiff base-oxazolidine condensation products with an aldehyde, which derivatives are more easily prepared than are the N-carbobenzyloxy protecting groups used in the method described in said copending application. Moreover, after preparation of the 2"-O-hydrocarbonsulfonylaminoglycoside derivative, the aldehyde blocking groups are more easily removed than are N- carbobenzyloxy groups and result in purer 2"-deoxy' 3"-desamino-2",3"-epimino-aminoglycoside interme diate over that obtained with carbobenzyloxy protected aminoglycosides. In addition to the foregoing, O-

protecting functions such as ketals, triphenylmethyl ethers, are also advantageously removed under the acidic conditions whereby the N-protecting-Schiff base-oxazolidine groups are cleaved, eliminating a step in the overall process of converting an aminoglycoside having a 2"-hydroxy function to a 2"- deoxyaminoglycoside.

SUMMARY OF THE INVENTION The process aspect of the invention sought to be patented resides in the improvement in a process for preparing a 2"-deoxy-3"-desamino-2",3-epiminoaminoglycoside, valuable as an intermediate, wherein an antibacterially active aminoglycoside having a 2"- hydroxy group and a 3"-amino function and having a primary and secondary amino groups protected by carbobenzyloxy groups, and also having protectable pri mary and secondary hydroxyl groups converted to O- protecting functions selected from the group consising of a triphenylmethyl ether of a primary hydroxyl group and a cyclic ketal or acetal of protectable neighboring hydroxyl groups, is treated with a hydrocarhonsulfonyl halide having up to eight carbon atoms in a tertiary amine, the thereby formed 2"-O-hydrocarbonsulfonyl- O-protected-per-N-carbobenzyloxyaminoglycoside is treated with a reagent selected from the group consisting of hydrogen in the presence of a catalyst, and an alkali metal in liquid ammonia whereby the N- carbobenzyloxy groups are removed; and the resulting 2 "-O-hydrocarbonsulfonyl-O-protectedaminoglycoside is converted to a 2"-deoxy-3"- desamino-Z",3"-epimino-aminoglycoside having protecting groups by means selected from the group consisting of spontaneous transformation and heating in a lower alkanol alone or together with an alkali metal salt of said alkanol at temperatures in the range of from about 25C to about 100C;

The improvement which comprises protecting primary amino groups and secondary amino groups capable of oxazolidine formation with an aldehyde and a neighboring hydroxyl group in said antibacterially active aminoglycoside by conversion thereof to Schiff base-oxazolidine condensation product with an aldehyde; and, after preparation of the 2"-O-hydrocarbonsulfonyl ester thereof, treating the resulting 2"-O- hydrocarbonsulfonylaminoglycoside having N- protecting-Schiff base-oxazolidine groups with dilute aqueous acid to a pH in the range of from about 1 to about 5, whereby said N-protecting-Schiff baseoxazolidine groups are removed.

A preferred species of the improvement process of this invention is that wherein the primary and secondary amino functions are converted to condensation products with benzaldehyde and wherein the protectable hydroxyl groups are converted to acetal functions with benzaldehyde whereby, after hydrocarbonsulfonylation of the 2"-hydroxy group, both the N- benzylidene, N,O-benzylidene and O-benzylidene protecting groups are easily and simultaneously removed under the reaction conditions of our process by acid treatment to a pH in the range of from about 1 to about 5, preferably with dilute hydrochloric acid, yielding a 2"-hydrocarbonsulfonylaminoglycoside which is converted to a 2-deoxy-3"-desamino-Z",3"-epiminoaminoglycoside intermediate free of O-protecting functions, which, upon hydrogenation in the presence of a catalyst, can be converted directly to a 2"- deoxyaminoglycoside free of O-protecting functions, thus eliminating the step of removing the O-protecting groups necessary in the prior art process utilizing N- carbobenzyloxy protecting groups.

Novel compositions-of-matter of this invention include 2"-O-hydrocarbonsulfonylaminoglycoside intermediates derived from known aminoglycoside antibacterials having a 2-hydroxy group and a 3"-amino function wherein primary amino functions and secondary amino functions capable of oxazolidine formation with an aldehyde and a neighboring hydroxyl group are protected by conversion thereof to Schiff baseoxazolidine condensation products with aldehydes and wherein protectable neighboring primary and secondary hydroxyl groups are converted to a member selected from the group consisting of a cyclic ketal or acetal selected from the group consisting of alkylidene, cycloalkylidene and arakylidene or wherein any primary hydroxyl group is converted to a triphenylmethyl ether.

Preferred intermediates are those wherein the 2"-O-hydrocarbonsulfonyl is 2-O-methanesulfonyl and wherein the N-protecting, N,O-protecting and O- protecting groups are benzylidenes. Of paticular value.

are 2"-O-methanesulfonyl-N,O-benzylidene-tetra-N- benzylidene derivatives of gentamicin C A, gentamicin C gentamicin C a, sisomicin, and verdamicin, 2-O- methanesulfonyl-O-benzylidene-N,O-benzylidene-tri- N -benzylidene derivatives of gentamicin B, gentamicin 4 B gentamicin X and Antibiotic G-4l8, 2-O methanesulfonyl-O-benZylidene-N,O-benzylidenetetra-N-benzylidene derivatives of Antibiotic Jl-20-A, Antibiotic .ll-20-B, and 2"O-methanesulfonyl-O- benzylidene-penta-N-benzylidene derivatives of tobramycin and of 3',4-dideoxykanamycin B.

COMPOUNDS USEFUL AS INTERMEDIATES Compounds of this invention useful as intermediates are novel derivatives of known aminoglycoside antibiotics having a 2"-hydroxy group and a 3"-amino function, including compounds selected from the group consisting of 2"-O-hydrocarbonsulfonylziminoglycosides such as defined by structural formulae Ila) and l(b) and KC) shown hereinbelow and the cyclic kctul and cyclic acctal derivatives thereof:

K was 4 I to) wherein M is a hydrocarbon radical having up to 8 carbon atoms; R and R are each members selected from the group consisting of hydrogen and hydroxy; R is a member selected from the group consisting of hydrogen and methyl; W is a member selected from the group consisting of hydroxy and N=X; W is a member selected from the group consisting of hydroxy, -N=X, and

benzylidene-3 ",4"-N,O-benzylidenegentamicin M being an aryl radical having up to 8 car bonatoms;

X is an organic radical bonded to the oxygen and the amino group through a bivalent carbon atom, and incan be an aliphatic, aromatic or heterocyclic radical.

Alkylidene radicals may be straight or branched and include, for example, ethylidene, propylidene, hyxylidene, decylidene, dodecylidene, and the isomeric' forms thereof. Cycloalkylidene radicals include cylcopropylidene, cyclopentylidene, cyclohexylidene, 3- cyclohexylpropylidene and the like.

Examples of aralkylidene radicals include benzylidene, Z-phenethylidene, 3-phenylpropylidene, naphthylidene, 3,6-dichlorobenzylidene, pnitrobenzylidene, p-chlorobenzylidene and the like. It is understood, of course, that the aryl nucleus can be substituted by functional groups such'as halogen, nitro, trifluoromethyl, lower alkyl and the like. Examples of suitable heterocyclic radicals are those derived from aromatic heterocyclic ring aldehydes such as aldehydes having furyl, thienyl, thiazolyl, thiadiazolyl, pyrazinyl, triazoyl, pyridyl, pyrazolyl, imidazolyl, oxazolyl, pyrimidinyl, pyrrolyl, dihydroimidazolyl, dihydropyridazinyl, benzimidazolyl, indazolyl, benzoxazylyl, pyrazolonyl, pyranyl, pyridazinyl, and dihydropyridazinyl rings and substituted derivatives thereof wherein the substituent can be, for example, lower alkyl, halogeno, and nitro.

The 2"-hydrocarbonsulfonyl derivatives contemplated are those derived from hydrocarbonsulfonic acids having up to 8 carbon atoms including ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, and preferably, methanesulfonic acid (i.e., compounds of formulae l(a), l(b) and l(c) hereinabove wherein M is ethyl, phenyl, p-tolyl, and methyl, respectively). A V

By protectable neighboring hydroxyl groups are contemplated vicinal and non-vicinal hydroxyl groups which together will form ketal and acetal functions with ketone derivatives and with aldehydes. Exemplary of such protectable hydroxyl groups are the 2,3,4'- hydroxy groups in gentamicin B and 8,, the 4',6'-

"hydroxy groups in gentamicin X and in Antibiotic G-4l8, the 3',4'-hydroxy groups in Antibiotics Jl-2- O-A and Jl-ZO-B, and the 4,6"-hydroxy groups in tobramycin and 3',4'- dideo xyl anamycin B. I

The cyclic ketal and acetal derivatives of said neighboring protectable hydroxyl groups of this invention include O-alkylidene (e.g., O-propylidene), O- cycloalkylidene (e.g., O-cyclohexylidene) and O- aralkylidene (e.g., O-benzylidcnc) derivatives.

Preferred intermediates of formulae l(a), l(b) and l(c) are those wherein M is methyl, and X is benzylidene, particularly the compounds of formula l(a) wherein W is benzylideneamino and the compounds of formula l( b), and which are derived from gentamicin C a, gentamicin C gentamicin C a, sisomicin and verdamicin. Included within this preferred group of intermediates are the following:

2-O-methanesulfonyl-l ,3,2,6-tetra-N- Cla (compound of formula l(a) wherein W is benzylideneamino and R R and R are hydrogen);

2"-O-methanesulfonyl-l ,3,2',6-tetra-N- benzylidene-3'f,4"-N,O-benzylidenegentamicin C (compound of formula l(a) wherein W is benzylideneamino, R and R are hydrogen and R is methyl, the stereochemistry at C-6 being R);

2"-O- methanesulfonyl-l,3,2',6'-tetra-N- benzylidene-3,4"-N,O-benzylidenegentamicin C2a (compound of formula l(a) wherein W is benzylideneamino, R and R are hydrogen and R is methyl, the stereochemistry at C-6 being S);

2 "-O-methanesulfonyl-1 ,3,2,6'-tetra-N benzylidene-3",4"-N,O-benzylidenesisomicin (compound of formula l(b) wherein R is hydrogen); and

2"-O-methanesulfonyl-l ,3,2',6-tetra-N- benzylidene-3",4"-N,O-benzylideneverdamicin (compound of formula l(b) wherein R is methyl).

Other useful intermediates of formulae l(a), l(b) and l(c) include those derived from gentamicin B, gentamicin B gentamicin X and Antibiotics .Il-20-A, Jl-2- 0-8 and G-4l8 which have protectable neighboring hydroxyl groups converted to a cyclic ketal or acetal thereof, preferably the benzylidene derivatives such as the following:

2' '-O-methanesulfonyl-2',3'(and 3 ,4 )-O- benzylide ne-l ,3,6'-tri-N-benzylidene-3 ",4"-N,O- benzylidenegentamicin B(a compound of formula l(a) wherein M is methyl, X is benzylidene, W is bcnzylideneamino, R is hydrogen,'and W R and R, are hydroxyl groups converted to the corresponding 2',3" (and 3',4 )-O-benzylidene acetal derivative thereof);

2"-O-methanesulfonyl-2',3'(and 3',4)-0- benzylidenel ,3,6'tri-N-benzylidene-3 ",4"-N,O- benzylidenegentamicin B 2"-O-methanesulfonyl-4,6'-O-benzylidene-l 3,2- tri-N-benzylidene-3",4"-N,O-benzylidenegentamicin X 2-O-methanesulfonyl-3 ,4'-O-benzylidene-l ,3 ,2- tetra-N-benzylidene-3"-N,O-benzylidene-Antibiotic Jl-ZO-A,

2-O-methanesulfonyl-3',4-O-benzylidene l,3,2,6- '-tetra-N-benzylidene-3 ',4' -N,O-benzylidene- Antibiotic JI20-B, and

2"-O-methanesulfonyl-4',6'-O-benzylidene-l ,3 ,2 tri-N-benzylidene-3",4"-N,O-benzylidene-Antibiotic G-4l8.

In addition to the foregoing, other valuable intermediates of this invention as defined by Formulas l(a), l(b) and [(0) are 2"-O-methanesulf0nyl and 2"-O-ptoluenesulfonyl-aminoglycosides having per-N- aralkylidene protecting groups other than per-N- benzylidene, e.g., per-N-(Z-phenethylidene). per-N- naphthylidene, per-N-(p-chlorobenzylidene), as well as 2"-O-mcthancsulfonyl and 2"-O-p-toluencsulfonyl aminoglycosidcs having per-N-alkylidene groups, e.g.. per-N-propylidene, or per-N-cyclo-alkylidene protecting groups, e.g., per-N-cyclohexylidene, particularly derivatives of aminoglycosidcs such as gentamicin C la, gentamicin C gentamicin C2a, sisomicin and verdamicin. Other valuable intermediates include the 4',6-O- benzylidene-per-N-benzylidene and the 4,6-N,O- propylidene-per-N-propylidene-derivatives of the 2"- O-methanesulfonyl esters of gentamicin X and of Antibiotic G-4l8, the corresponding 3",4"-N,O- benzylidene-per-N-benzylidene and 3,4'-N.O- propylidene-per-N-propylidene derivatives of the 2"- O-methanesulfonyl esters of Antibiotic Jl-20A and Jl-ZO-B, as well as the product mixtures comprising the and propylidene derivatives of the 2"-O-methanesulfonyl esters of gentamicin B and gentamicin B Also included within this invention are 2"-O-hydrocarbonsulfonyl derivatives of formulae 1(a), I(b) and I(c) having primary hydroxyl groups protected as an ether derivative, e.g., an O- triphenylmethyl ether derivative, such as:

2 "-O-methanesulfonyl-6-O-triphenylmethyll,3,2,6',3"-penta-N-benzylidene tobramycin,

'2"-O-methanesulfonyl-6"-O-triphenylmethyll,3,2',6',3"-penta-N-benzylidene-3',4- dideoxykanamycin B,

2"-O-methanesulfonyl-6-O-triphenylmethyll ,3,2- tri-N-benzylidene-3 ",4 '-N ,O-benzylidenegcntamicin X2.

Other valuable intermediates are the 2"-O-ptoluene-sulfonyl-6'-N-p-toluenesulfonyl-per-N-ylidene derivatives of gentamicin C e.g., 6',2"-di-N,O-ptoluenesulfonyl-l,3,2'-tri-N-benzylidene-3",4"-N,O- benzylidenegentamicin C and 6',2"-di-N,O-ptoIuenesulfonyl-l ,3,2'-tri-N-propylidene-3,4"-N,O- propylidenegentamicin C The 2"-O-hydrocarbonsulfonyl-per-N-ylideneaminoglycoside derivatives of formulae 1(a), I(b), and =I(c) are valuable as intermediates in our improved process for preparing 2"-deoxy-3"desamino-2",3"- epiminoaminoglyeosides, in turn valuable as intermediates in preparing 2"-deoxyaminoglycosides and the 2"- epi-amino-3-desamino analogs therof having antibacterial activity.

The preparation of the novel intermediates of formulae 1(a), I(b) and from an antibacterially active 'aminoglyeoside having a 2"-hydroxyl group and a 3"- amino function is described hereinbelow in the description of the process aspect of this invention.

GENERAL DESCRIPTION OF THE PROCESS ASPECT OF THE INVENTION N Ha II (b) v wherein R is a member selected from the group consisting of amino and hydroxy; R and R' are each members selected from the group consisting of hydrogen and hydroxy; R' R";; and R"; are each members selected from the group consisting of hydrogen and methyl; R' is a member selected from the group consisting of hydroxy, amino and methylamino; and R is a member selected from the group consisting of hydrogen and hydroxymethyl.

Typical intermediates of formulae [1(a) and II(b) are as follows:

2"-deoxy-3-desmethylamino-2",3"-N- methylepiminogentamicin Cla,

2"-dcoxy-3"-desmcthylamino-Z",3"-N- methylepiminogentamicin C2,

2"-deoxy-3"-desmethylamino-2",3"-N- methylepiminosisomicin,

2"-de0xy-3"-desmethylamino-2",3"-N- methylepiminogentamicin X2, and

2"-deoxy-3"-desamino-2,3"-epiminotobramicin.

Compounds of formulae II(A) and ll(b) are prepared and, in'turn, are converted to antibacterially active 2"- deoxyaminoglycosides (i.e., 2"-deoxy-nonderivatized analogs of formulae I(a), I(b) and I(c) and 3"- desamino-2"-epi-amino-analogs thereof, according to a process described in co-pending application Ser. No. 300,083, whereby an antibacterially active aminoglycoside having a 2-hydroxy function and a 3"- primary or secondary amino function, and having primary and secondary amino functions protected by N- carbobenzyloxy groups and protectable neighboring primary and secondary hydroxy groups derivatized, is converted to a per-N-carbobenzyloxy-Z-O-hydrocarbonsulfonate ester followed by removal of the carbobenzyloxy groups, usually by hydrogenation in the presence of a catalyst or, when easily reduceable double bonds are present in the molecule such as the 4',5'- double in sisomicin and verdamicin, by cleavage with an alkali metal (e.g., lithium, sodium or potassium) in liquid ammonia, using 2 gm. atoms of said alkali metal for each carbobenzyloxy group present. The 2"-O-hyd'rocarbonsulfonate ester having free amino groups thereby formed either spontaneously ring closes in situ to form a 2"-deoxy-3" -desamino-2",3"- epimino-aminoglycoside intermediate, or the conversion is effected by heating the 2"-O-hydrocarbonsulfonate ester in a lower alkanol (e.g., methanol) either alone or together with an equivalent molar quantity of an alkali metal salt of said alkanol (e.g., sodium methylate) at temperatures in the range of from about 25C to about C. The epimino (or methylepimino) intermediate thereby formed is then treated with hydrogen in the presence of a catalyst (e.g., palladium on charcoal) or by other described methods followed by acid hydrolysis of any ketal or acetal functions which may be present whereby is formed a product mixture eomprising a 2"-deoxy-aminoglycoside together with a 2"- deoxy-fl-tlesmcthylamino (or dcsumiuo)- nminoglyeositle which mixture is separable via ehro matogruphic techniques.

In the improved process of this invention, the primary and secondary amino functions in the aminoglycoside starting compound are protected as Schiff base-oxazolidine condensation products with aldehydes (preferably N-benzylidene and N,O-benzylidene derivatives) which, after preparation of the 2"-O-hydrocarbonsulfonate ester, are conveniently remo v e d by tre atm ent with dilute aqueous acid. The use carbobenzyloxy process outlined hereinabove, in that' the N-Schiff base and N,O-oxazolidine groups are usually easier to prepare and easier and less expensive to remove than are the N-carbobenzyloxy protecting groups of my process, and their use in our process usually results in higher yields of the 2"-deoxy-3"- desamino (or desmethylamino)-2",3"-epimino (or N- methylepimino)-aminoglycoside key intermediate of the process.

Removal of the prior a;tEiiBdsmiiiiy' fiie'iisg groups requires hydrogenation techniques which must be carried out under carefully controlled conditions and which require expensive catalysts: whereas removal of the Schiff base-oxazolidene protecting groups of our invention requires only the addition of dilute acid to a solution of the N-protected-intermediate. Our improved process is particularly useful when converting aminoglycosides having easily reduceable double bonds, e.g sis omicin and verdamicin, which are unafwith'the Schiff base-oxazolidine groups upon treatment with acid, thus advantageously eliminating a step in the overall process of converting a 2 hydroxyaminoglycoside to a 2"-deoxyaminoglycoside. Our improved process is indicated schematically hereinbelow in Chart A wherein only the 3"-amino sugar ring of the aminoglycosides of the invention are shown, the Roman numeral below a partial formula referring to 'the complete structural formula similarly l0 identified hereinabove, the substitutent V designat ing the two rings of the aminoglycosides as disclosed in formulae 1(a), l(b), l(c), ll(a) and ll(b) hereinabove. the V substituent of intermediate A including the two upper rings as defined by both formulae ll(a) and ll(b) hereinabove, the substituent V of starting compound A including the two other rings of tobramyein and of 3,4'-dideoxykanamycin B, i.e., rings as defined by formula ll(a) wherein R and R are each amino. R and R are each hydrogen, R is hydrogen or hydroxy, the substituents R R R M and X being as heretofore defined for formulae 1(a), l(b) and l(c).

CIIZOII V I H0 /i 0 /i\ o NCH NIlQ H3O 1/ H0 \I OH OH A An Aldehyde A An Aldehyde l in neutral l in neutral medla media CHzOH v' 0 0 i*" o i\ Derivatize i (g protectable HO 1 H3 l Wa t r wr a e y e, B 0H PTSA/DMF 0H MSO2 halide in a tertiary amine \i' CH; V 0 l o 0 0 X I(N(II i \i i i l 1 3 g fl r l- "l l-l 0- -HO2M ()flOuM 1(a) and 1(b) [(0) 11+ N (DH 013115) (pHil to pH 5) T115 v R115 V O l 0 l 1 O 0 R 4 R3 spontaneously, /l

13 1 v Aal A NHR" i H0 V 0ne,or 0 a plus alkah l nlllegtal in i (i a ano S0 M II(a) and 1I(b) 2 Chart A fected under the conditions of the process of this inven- 7 tion, but which become reduced when carbobenzyloxy groups are cleaved by hydrogenation in the presence of a catalyst, thus necessitating removal of the carbobenzyloxy groups by means of an alkali metal in liquid ammonia, a much more time consuming and expensive procedure than removal of the Schiff base-oxazolidine protecting groups of this invention.

Additionally, by our improved process, any 0- protecting groups which may be present in the molecule, e.g., acetals (preferably O-benzylidene) and O- triphenylmethyl ethers, are removed simultaneously pounds can be antibiotics such as gentamicin C or derivatives of antibiotics such as 3',4'-dideoxykana'mycin B. i

Typical starting aminoglycoside antibacterials are such as the gentamicins (including gentamicin B, gentamicin B gentamicin C gentamicin Cla, gentamicin C2, gentamicin C2a, gentamicin X and mixtures thereof), sisomicin, verdamicin, Antibiotic Jl-20-A, Antibiotic Jl-20-B, Antibiotic G-418, tobramycin and 3, 4-dideoxykanamycin B.

Most of the aforementioned aminoglycoside antibiotics are known. Of the gentamicins, the starting compound referred to herein as gentamicin X is also known in the art as gentamicin X; the starting compounds referred to herein as gentamicin C and gentamicin C2a are stereoisomeric with each other about the carbon at the 6'-position (i.e., the 6-carbon atom) gentamicin C being a 2-hydroxy derivative of formula 1(a) hereinabove wherein R is methyl, R is amino, and the stereochemistry at C-6 is R; gentamicin C2a being a 2"-hydroxy derivative of formula 1(a) wherein R is methyl, R is amino, and the stereochemistry at C-6' is S. The isolation, properties and planar configuration of gentamicin C is described in US. Pat. No. 3,651,042; while the isolation, properties and planar configuration of gentamicin C2a, as well as the stereoconfiguration about C-6 of gentamicin C and C2a, is described in copending application of common assignee as that of theinstant application of Peter J. L.

Daniels and J. A. Marquez, entitled Novel Antibiotic from Micromonospora, Ser. No. 269,914 filed July 7,

Verdamicin, Antibiotic G-4l8, Antibiotic Jl--A and Antibiotic Jl-20B are all also described in copending U.S. applications of common assignee as that of the instant application; verdamicin being described in US. application Ser. No. 208,907 filed Dec. 16, 1971 as a continuation-in-part of US. Ser. No. 58,050 filed July 24, 1970, and both now abandoned, of M. J. Weinstein, G. H. Wagman, and J. Marquez entitled Antibiotics and Process for Their Manufacture; Antibiotic G-418 being described in application U.S. Ser. No. 196,707 filed Nov. 8, 1971, now abandoned, of M. J. Weinstein, G. H. Wagman, R. Testa and J. Marquez entitled Antibiotic G-4l8 and Production Thereof; while Antibiotics Jl-20-A and Jl-20-B are described in application U.S. Ser. No. 261,753 filed June 12, 1972, now abandoned, of Jan Ilavsky, Aris P. Bayan, William Charney and Hans Reimann entitled New Antibiotic from Micromonospora Purpurea 11-20.

ln our improved process as indicated schematically in Chart A, to prepare the requisite N-protected intermediates Band B an aminoglycoside having a 2"-hyd roxy group and a 3"-primary or secondary amino function (designated as compounds A and A in Chart A) is condensed with an aldehyde (preferably benzaldehyde) in an inert organic solvent utilizing techniques known in the art for preparing Schiff base-derivatives, whereby are formed Schit'f base-derivatives (i.c., N-ylidenes. e.g., N-hcnzylidene) of primary amines therein (as illustrated by the 3.'-(N==X )-derivative of'tormulu B in Chart A) and oxazolidinc derivatives (i.e., N,O- ylidenes, e.g., N,O-benzylidenes) of secondary amines therein which are capable of oxazolidine formation with an aldehyde and a neighboring hydroxyl group (as illustrated by the 3",4"-N,O-oxazolid,ene derivative in compound B of Chart A).

Aldehydes useful .for forming-N-protecting derivatives in our improved process include aldehydes having aliphatic, aromatic or heterocyclic radicals optionally substituted by functional groups as disclosed hereinabove in the description of the products of this invention. Since the process of this invention involves reactions of the 2"-hydroxy function of the aminoglycoside, it is preferable that the aldehyde with which the aminoglycoside starting compound is condensed be devoid of hydroxyl groups. Benzaldehyde is a convenient condensing reagent in our improvement process whereby are formed good yields of crystalline per-N- benzylidene-3",4"-N,O-benzylideneaminoglycosides of formula B (Chart A) and per-N- benzylideneaminoglycosides of formula B (Chart A) wherein :2 benzylidene.

To minimize competing reactions when converting the 2-hydroxyl group to a 2"-O-hydrocarbonsulfonyl ester derivative according to the prior art process, the primary hydroxyl groups and protectable neighboring hydroxyl groups in aminoglycoside starting compounds are also usually protected prior to reaction with a hydrocarbonsulfonyl halide as shown in Chart A, preferably as a cyclic acetal or cyclic ketal of vicinal and neighboring hydroxyl groups or as an ether (preferably a triphenylmethyl ether, also called a trityl ether) of any primary hydroxyl groups. Thus, prior to the conversion of the starting compounds (A and A) to the 2"-O-hydrocarbonsulfonate esters 1(a), 1(b) and 1(e), and, after the primary and secondary amino functions have been converted to N-ylidene and N,O -ylidene derivatives, vicinal hydroxy groups such as those at the 3 and 4' positions in Antibiotics .ll-20-A and Jl-20--B and those at the 2,3, and 4 positions in gentamicin B and B are converted to a cyclic ketal (e.g., to a 3',4-

O-isopropylidene) or to a cyclic acetal (e.g., to a 3,4 O-benzylidene) by reaction thereof according to methods known in sugar chemistry as exemplified in the Procedures hereinbelow. In the case of gentamicin B and 8,, mixtures of the 3,4' and 2, 3'-O-ylidene derivatives are formed, which mixtures can be used. as is, in our process. Primary hydroxyl groups such as are present at C-6' in gentamicin A and X or at C-6" in tobramycin and 3,4'-dideoxykanamycin B can be protected by conversion to the corresponding trityl ether by reaction with 'triphenylmethyl chloride in pyridine or, together with a neighboring hydroxyl group, by conversion to a cyclic acetal, e.g., to the 4, 6'-O- isopropylidene derivatives of gentamicin A and of gentamicin X and to the 4",6"-O-iso-propylidene derivatives of tobramycin and 3',4'-dideoxykanamycin B. Exemplary of other protectable, neighboring hydroxyl groupsis the grouping of secondary hydroxyl groups at C-3',C-4', and C-6' in Antibiotic G4l8 which form a 4,6'-O-ylidene derivative when reacted with dimethoxypropane or benzaldehyde, for example.

In our improved process, we have found it most convenient to convert protectable hydroxyl groups to :1 cyclic acetal derived from the same aldehyde, preferably benzaldehyde, utilized for the N-protecting Schitl baseoxazolidine derivatives. Thus. treatment of l..l.2',(1- tetra-N-benzylidene-3",4"-N.O-benzylidene- Antibiotic Jl-20-A with benzaldehyde and p-toluenesulfonic acid in dimethylformamide according to known procedures for preparing acetals yields the corresponding O-benzylidene derivative, i.e., 3',4-O-

benzylidene-l,3,2",6-tetra-N-benzylidene-3",4"-N,O-

benzylidene Antibiotic Jl--A.

After conversion of the amino-groups to N-yliden-e and N,O-ylidene "derivatives and derivatization of the protectable hydroxyl functions, the 2"-hydroxy group in the aminoglycoside intermediate (B or B) is converted to the corresponding hydrocarbonsulfonate ester, i.e., to a 2"-O-hydrocarbonsulfonyl derivative by treatment of said 2"-hydroxyaminoglycoside with a halide of a hydrocarbonsulfonic acid in a tertiary amine (a preferred reagent mixture being methanesulfonyl h eri in t yr i -,v

Any hydrocarbonsulfonic acid halide having up to eight carbon atoms is preferable for use in this step of our process, including the acid bromide and acid chloride derivatives of methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid and p-toluenesulfonic acid, methanesulfonyl chloride being a reagent of choice.

Among the tertiary amines contemplated as suitable for use in the esterification step are tertiary aliphatic and aromatic amines including cyclic amines such as trimethylamine, triethylamine, collidine, dimethylaminopyridine and, preferably, pyridine, which serve both as solvent and basic agent.

A convenient method of carrying out a preferred species of this esterification step (i.e., that which utilizes methanesulfonyl chloride in pyridine as the esterification medium) comprises preparing a solution of the aminoglycoside antibiotic having all primary and secondary amino groups and vicinal hydroxyl groups protected, e.g., penta-N-benzylidenegentamicin C in dry pyridine to which is then added an acid halide, e.g., methanesulfonyl chloride, in amounts of from about 1 to 1.5 moles of acid halide per mole of aminoglycoside (usually about 1.1 moles of acid halide), and allowing this solution to stand at room temperature (about C) for a period of about one to 6 hours, usually 3 hours. Anhydrous alkanol, e.g., methanol, is then added to decompose any excess sulfonic acid halide and the 2"-O-hydrocarbonsulfonyl derivative thereby prepared, e.g., 2"-O-methanesulfonyl-penta-N- benzylidenegentamicin C is then conveniently isolated and purified utlilzing techniques known in the art such as solvent distillation, solvent extraction, precipitation, crystallization, chromatography and the like.

ln our improved process, the 22"-()- hydrocarbonsulfonyl-per-N-ylidene-O-protectedaminoglycoside intermediate, after isolation as described hereinabove, can be used without further purification in the next step of our process whereby both the per-N-Schiff base-oxazolidine and the O-protecting groups are simultaneously removed by treatment with dilute acid to a pH in the range of from about 1 to about 5. The resulting 2"-O-hydrocarbonsulfonate ester having free amino and free hydroxyl groups may spontaneously ring close in situ under the conditions of the reaction or of the isolation or purification of the product whereby is formed a 2"-deoxy-3"-desamino- 2",3"-epimino-aminoglycoside (ll(a) and ll(b)); alternatively, the conversion is effected by heating the 2"-O-hydrocarbonsulfonate ester in a lower alkanol (e.g., methanol) either alone or together with an equivalent molar quantity of an alkali metal salt of said alkanol (e.g., sodium methylate) at temperatures in the range of from about 25C to about 100C.

The 2"-deoxy-3"-desamino-2",3"-epiminoaminoglycosides (ll(a) and ll(b)) are convertible to antibacterially active 2"-deoxyaminoglycosides and their 3-desamino (or desmethylamino)-2"-epi-amino(or epi-methylamino) analogs thereof by hydrogenation in the presence of a catalyst or by other methods such as described in aforementioned copending application Ser. No. 300,083 of Peter J. L. Daniels.

A preferred mode of our improved process is that utilizing benzaldehyde as acetalizing agent, wherein the aminoglycoside requires only N-derivatization, and wherein the amino groups present are all either primary or are secondary amines capable of forming oxazoli dine derivatives with an aldehyde and a neighboring hydroxyl group. Aminoglycosides within this preferred group are gentamicin Cla, gentamicin C gentamicin C2a, sisomicin and verdamicin. A convenient method of carrying out our improvement process comprises stirring together at room temperature a solution of an aminoglycoside (e.g., sisomicin) in an inert nonreactive organic solvent (e.g., benzene), with an excess of an aldehyde (e.g., benzaldehyde) until the starting aminoglycoside has all reacted as evidenced by thin layer chromatography. The per-N-Schiff baseoxazolidine derivative thereby prepared (e.g. 1.3.2.,6- '-tetra-N-benzylidene-3",4"-N,O- benzylidenesisomicin) is easily isolated as a white solid by evaporation of the solvent, purified by known techniques such as crystallization or chromatography. and then converted to the corresponding 2"-O-hydrocarbonsulfonate ester (preferably the 2"-O- methanesulfonate) in the manner disclosed hereinabove and in the examples. The Schiff base-oxazolidine protecting groups are then conveniently removed in dilute acid, any mineral acid being suitable, particularly sulfuric acid, perchloric acid, and preferably hydrochloric acid. Usually, the 2"-O-hydrocarbonsulfonylper-N-ylidene-aminoglycoside (e.g., 2"-O- methanesulfonyl-1,3,2 ,6' tetra-N-benzylidene-3 ",4"- N,O-benzylidenesisomicin) is dissolved in a lower alkanol (e.g., methanol) and an' excess quantity of dilute acid is added and the reaction mixture stirred at room temperature for several hours with the pH of the reaction mixture being between 1 and 5. The solution containing the 2"-O-hydrocarbonsulfonylaminoglycoside free of N-protecting groups (e.g., 2"-O- methanesulfonylsisomicin) is evaporated, and the residue purified by chromatography, such as column chromatography over silica gel eluting with the lower phase ofa 2:l:l mixture of chloroform-methanol-l 5 percent ammonium hydroxide. In this preferred species. under the foregoing conditions, the 2"-O-hydrocarbonsulfonyl-aminoglycoside spontaneously transforms to a 2",- 3"-epimino-amino-glycoside of formula ll(a and b). e.g., 2"-deoxy-3"-desmethylamino-2",3"-N- methylepiminosisomicin.

In our improvement process, the 2"-O-hydrocarbonsulfonate ester of choice is usually the 2"- methanesuifonate ester; however, the 2"-p-toluenesulfonate ester is preferred when converting gentamicin C, to 2"-deoxy-3"-desmethylamino 2",3"-N- methylepimino-gentamicin C, by our improved process. Gentamicin C, has a secondary amino function at C-6' which does not form a stable aldehyde addition compound. Thus, upon condensation with an aldehyde, e.g. benzaldehyde, gentamicin C, is converted to 1,3,2-

, V -tri-N-benzylidene-3",4"-N,O-benzylidenegentamicin C, with the secondary amine at C6 unprotected.

Treatment of the foregoing derivative with 2.2 moles of p-toluenesulfonyl chloride per mole of aminoglycoside derivative yields the desired 2-O-ptoluenesulfonylaminoglycoside with the 6-amino'function masked by a p-toluenesulfonyl group, i.e, to 6',2"- di-N,O-p-toluenesulfonyl-l ,3 ,2 -tri-N-benzylidene- 3",4"-N,O-benzylidenegentamicin C Upon treatment with dilute aqueous acid according to our process, the per-N-benzylidene groups are removed and the 2"-O- sulfonate ester derivative is eliminated by ring closure with the N-sulfonyl protecting group remaining to form 2"-deoxy-3"-desmethylamino-2",3"-N- methyllepimino-6'-N-p-tolu-enesulfonylgentamicin C The 6'-p-toluenesulfonyl group is then conveniently removable via electrochemical reduction.

The process of our invention shown in Chart A is illustrated in detail hereinbelow in the examples which should not be construed as limiting the invention in spirit or in scope.

Preparation 1 Schiff base-oxazolidine-aminoglycoside Derivatives A. Per-N-benzylideneaminoglycosides l. l,3,2',6'-tetra-N-benzylidene-3",4"-N,0-

. benzylidenesisomicin Add 5.65 ml. of benzaldehyde to 5 g. of sisomicin in 100 ml. of dry benzene. Stir together at room temperature until no starting material (sisomicin) is present as evidenced by thin layer chromatography (about 21 hours reaction time). Evaporate the benzene followed by drying in vacuo to give a residue (8.9lg.) comprising l,3,2',6"-tetra-N-benzylidene-3 ,4"-N,O- benzylidenesisomicin. Purify by crystallization from chloroform-hexane as follows: dissolve a sample of the foregoing pentabenzylidene derivative in a minimum of chloroform and add hexane to incipient turbidity. Allow the solution to stand until crystallization appears complete, then filter and dry the resultant crystalline precipitate comprising the purified pentabenzylidenesisomicin, m.p. 123-126C; [a] 42 (0.3 percent in chloroform).

' 2. In a manner similar to that described in Prepara tion,1A (l), treat each of the following aminoglyeosides with benzaldehyde in dry benzene:

gentamicin C gentamicin C gentamicin C gentamicin C verdamicin,

Antibiotic Jl--A,

Antibiotic .lI-20-B,

gentamicin B,

gentamicin B,,

Antibiotic G4l8,

tobramycin,

3',4-dideoxykanamycin B, and

gentamicin X Isolate and purify each of the resultant products in a manner similar to that'described in Preparation lA( l) to obtain respectively:

l,3,2-tri-N-benzylidene-3,4"-N,O- benzylidenegentamicin C 1,3 ,2',6'-tetra N-benzylidene-3 ',4 -N ,O-benzyligemtami in Q10).

1 ,3,2,6'-tetra-N-benzylidene-3",4--N ,obenzylidenegentamicin C m.p. =205.5--2l2.2C;

[a] 'l6.8(0.3 percent in chloroform),

LII

1,3 ,2,6'-tetra-N-benzylidene-3", 4 -N,O- benzylidenegentamicin C l,3,2,6'-tetra-N'-benzylidene-3 ",4"-N ,O- benzylideneverdamicin,

1,3 ,2,6-tetra-N-benzylidene-3 ",4"-N ,O-benzylidene-Antibiotic Jl-20-B,

1,3,6-tri-N-benzylidene-3,4"-N,O- benzylidenegentamicin B,

l,3,6'-tri-N-benzylidene-3 ",4"-N,O-benzylidenegentamicin B l,3,2'-tri-N-benzylidene-3',4"N,O-benzylidene- Antibiotic G4l8,

l,3,2',6'3 '-penta-N-benzylidene tobramycin,

1,3,2 ,63 '-penta-N-benzylidene-3 ,4 '-dideoxykanamycin B, and

l,3,2'-tri-N-benzylidene-3",4-N,)- benzylidenegentamicin X B..Other Schiff base-Oxazolidine Derivatives 1. In the procedure of Preparation lA(l) in place of benzaldehyde there may be substituted other aldehydes such as propionaldehyde, p-chlorobenzaldehyde or 1- naphthaldehyde and there is obtained the corresponding per-N-ylidene derivative, i.e., l,3,2',6'-tetra-N- propylidene-3,4"-N,O-propyliden esisomicin, l,3.2',- 6'-tetra-N-p-chlorobenzylidene-3,4"-N.O-pchlorobenzylidene-sisomicin, and l,3,2'.6-tetra-N- naphthylidene-3",4"-N,O-naphthyli-denesisomicin, respectively.

2. In similar manner to that described in Preparation 1A (2), by substituting for benzaldehyde other aldehydes such as propionylaldehyde, pchlorobenzaldehyde or l-napthaldehyde there is obtained the corresponding Schiff base-oxazolidine derivative respectively for each of the aminoglycoside starting compounds listed therein.

Preparation 2 O-Benzylidene-per-N-benzylideneamin oglycosides A. O-Benzylidene-per-N-benzylideneaminoglycosides l. b 4,6"-O-Benzylidene-l,3,2',6',3"-benzylidenetobramycin To a solution of 5g. of 1,3,2',6,3"-penta-N-benzylidene-tobramycin in 25 ml. of anhydrous dimethylformamide add 1 ml. of benzaldehyde and 300 mg. of dry p-toluenesulfonic acid. Heat in a sealed flask at l 10C for 4 hours, cool the solution, then treat the cooled solution with 6 ml. of Amberlite lR-40lS resin in the hydroxide form. Filter'off the resin and evaporate the liltrate in vacuo to a residue comprising 4",6"-O- benzylidene-l,3,2',6,3"-penta-N-benzylidenetobramycin which can be used without further purification as an intermediate in the process set forth hereinbelow in the examples.

A purified sample is prepared by crystallization in a manner similar to that described in Preparation lA( l 2. Treat the following per-N- benzylideneaminoglycosides with benzaldehyde and dry ptoluenesulfonic acid in dimethylformamide in the manner described in Preparation 2A( 1 1,3,2,6',3"-penta-N-benzylidene-3',4'- siiis tx sitear iriafit .7

I ,3,2,6 -tetra-N-benzylidene-3 ',4 '-N,O-benzylidene-Antibiotic JI-20-A,

I ,3 ,2,6 '-tetra-N-benzylidene-3 ',4 '-N,O-benzylidene-Antibiotic JI-20-B,

1,3,2 '-tri-N-benzylidene-3 ",4' '-N,O-benzylidene- Antibiotic G-l44l 8,

l,3,2-tri-N-benzylidene-3 ",4"-N,O- benzylidenegentamicin X l,3,6-tri-N-benzylidene-3 ",4-N,O- benzylidenegentamicin B, and

l,3,6'-tri-N-benzylidene-3",4 -N,O- benzylidenegentamicin B Isolate and purify each of the above resulting products in a manner similar to that described in Preparation 2A (1) to obtain respectively:

4",6"-O-benzylidene-1,3,2,6',3"-penta-N- benzylidene-3',4 dideoxykanamycin B,

3',4'-O-benzylidene-l ,3,2',6-tetra-n-benzylidene- 3",4"-N,O-benzylidene-Antibiotic JI-20-A,

3 ,4'-O-benzylidene-1 ,3,2',6'-tetra-N-benzylidene- 3",4"-N,O-benzlidene-Antibiotic JI-20-B,

4',6'-O-benzylidene-l ,3,2'-tri-N-benzylidene-3",4"- N,O-benzylidene Antibiotic 6-4 I 8,

4',6'-O-benzylidene-l ,3,2-tri-N-benzylidene-3",4"-

N,O-benzylidenegentamicin X a mixture comprising 2',3(and 3',4')-O- benzylidene- 1,3,6'-tri-N-benzylidene-3",4"-N,O- benzylidenegentamicin B, and

a mixture comprising 2 ,3 (and 3 ,4)-O-benzylidene- I,3,6'-tri-N-benzylidene-3"4"-N,O- benzylidenegentamicin B EXAM L J A. 2-O-methanesulfonyl-1,3 ,2 ',6 '-tetra-N- benzylidene-3",4"-N,O-benzylidenegentamicin C 1. Dissolve 0.5 g. of l,3,2',6-tetra-N-benzylidene- 3",4"-N,O-benzylidenegentamicin C in IO ml. of dry pyridine and evaporate the pyridine in vacuo to a residue. Repeat this process with an additional 10 ml. of dry pyridine. Then dissolve the resultant dry residue in 5 ml. of dry pyridine and add dropwise a solution of 0.05 ml. of methanesulfonyl chloride in 5 ml. of pyridine. Stir the reaction mixture at room temperature for 16 hours, then evaporate in vacuo to a residue comprising 2"-O-methanesulfonyl-l ,3 ,2 ,6-tetra-N- benzylidene-3",4"-N,O-benzylidenegentamicin C, which can be used without further purification as an intermediate in the procedure of Example 2A.

2. In the above procedure, by substituting for per-N- benzylidenegentamicin C other per-N-ylidene derivatives of gentamicin C there is obtained the corresponding 2"-O-methane-sulfonyl ester, e.g., by treating I,3,2',6-tetra-N-propylidene-3",4"-N,O- propylidenegentamicin C with methanesulfonyl chloride in pyridine there is obtained 2"-0- methanesulfonyll,3,2',6-tetra-N-propylidene- 3",4"-N,O-propylidenegentamicin C B. In a manner similar to that described in Example IA, treat each of the following per-N- benzylideneaminoglycosides with methanesulfonyl chloride in pyridine:

l,3,2',6-tetra-N-benzylidene-3 ',4"-N ,O-benzyli-' dene-sisomicin,

1,3 ,2 ',6 '-tetra-N-benzylidene-3 ',4 -N ,O-benzylidene-gentamicin C l,3,2',6-tetra-N-benzylidene-3 ",4"-N ,O- benzylidenegentamicin C l,3,2',6'-tetra-N-benzylidene-3 ,4 -N ,O- benzylideneverdamicin.

Isolate and purify each of the respective products in a manner similar to that described in Example IA to obtain:

2' -O-methanesulfonyl-l .3,2',6'-tetra-N benzylidene-3",4"-N,O-benzylidenesisomicin,

2"-O-methanesulfonyl-l ,3,2',6'-tetra-N- benzylidene-3",4"-N,O-benzylidenegentamicin C 2"-O-methanesulfonyl-l ,3,2,6'-tetra-N- benzylidene-3",4"-N,O-benzylidenegentamicin C 2"-O-methanesulfonyl-I ,3,2,6-tetra-N- benzylidene-3",4"-N,O-benzylideneverdamicin.

In similar manner, other per-N- ylideneaminoglycosides may be used in place of the per-N-benzylidene derivatives in the procedure of Example IB and there is obtained the corresponding 2"- O-methanesulfonyl-per-N-ylidene derivative. e g.. treatment of l,3,2',6'-tetra-N-p-chlorobenzylidenc- 3",4'-N,Op-chlorobenzylidenesisomicin with methhanesulfonyl chloride in pyridine yields 2"-O- methanesulfonyll ,3 ,2 ,6 -tet r a-N pchlorobenzylidene 3 ,4'-N,O pchlorobenzylidenesisomicin.

C. 2"-O-methanesulfonyl-O-benzylidene-per-N- benzylideneaminoglycosides In a manner similar to that described in Example 1A treat each of the following O-benzylidene-per-N- benzylideneaminoglycosides with methanesulfonyl chloride in pyridine:

4",6"-O-benzylidene-l ,3',2',6,3"-penta-N-benzylidenetobramycin,

4",6"-o-benzylidene-l,3,2',6',3'f-penta-N- benzyIidene-3,4-dideoxykanamycin B,

3 ,4'-O-benzylidene-1 ,3 ,2',6-tetra-N-benzylidene- 3",4"-N,O-benzylidene-Antibiotic JI-ZO-A,

3 ',4-O-benzylidene-l ,3,2',6'-tetra-N-benzylidene- 3",4"-N,O-benzylidene-Antibiotic .II-20-B,

4,6-O-benzylidenel ,3,2'-tri-N-benzylidene-3 ',4"- N,O-benzylidene-Antibiotic 6-4 I 8.

4,6-O-benzylidene-l ,3,2-tri-N-benzylidene-3,4- N,O-benzylidenegentamicin X a mixture comprising 2',3(and 3,4')-O- benzylidene-l ,3,6-tri-N-benzylidene-3 ,4"-N,O- benzylidenegentamicin B, and

a mixture comprising 2',3(and 3',4')-O- benzylidene-l ,3,6-tri-N-benzylidene-3 ",4' '-N,O- benzylidenegentamicin B Isolate each of the respective products in a manner similar to that described in Example IA to obtain the following 2"-O-methanesulfonyl derivatives:

2"-O-methanesulfonyl-4",6"-O-benzylidenel,3,2,6,3"-penta-N-benzylidenetobramycin,

2"-O-methanesulfonyl-4",6"-O-benzylidenel,3,2',6',3"-penta-N-benzylidene-3',4'- dideoxykanamycin B,

2'-O-methanesulfonyl-3,4'-O-benzylidene- I ,3.2',6'- tetra-N-benzylidene-3",4"-N,O-benzylidene- Antibiotic .ll-20A,

2"-O-methanesulfonyl-3,4'-O-benzylidenel,3,2',6'-tetra-N- benzylidene-3",4"-N.O-benzylidene-Antibiotic O-B,

19 2"-O-methanesulfonyl-4,6'-O-benzylidene-1,3,2- tri-N-benzylidene-3 ,4 -N,O-benzylidene-Antibiotic G418,

2"-O-methanesulfonyl-4',6'-O-benzylidene-1,3 ,2 tri-N-benzylidene-3 ,4 '-N,O-benzylidenegentamicin a mixture comprising 2' '-O-methanesulfonyl- 2,3(and 3,4')-O-benzylidene-1,3,6'-tri-N- dene-tobramycin in 100 ml. of dry pyridine. Evaporatev the pyridine to remove any trace of water, then repeat this process. Dissolve the dried residue in 75 ml. of pyridine and at room temperature, add 3 g. of triphenylmethyl chloride. Shake the mixture until all the triphenylmethyl chloride has dissolved and then allow the reaction mixture to stand at room temperature for 5 days. To the resulting solution of 6"-O- triphenylmethyll ,3,2',6 ,3 '-penta-N- benzylidenetobramycin, add 1.75 g. of methanesulfonyl chloride and allow the mixture to stand an additional 24 hours. Evapor'ate the pyridine in vacuo to a residue comprising 2-O-methanesulfonyl- 6-O-triphenylmethyl- 1,3,2,6',3"-penta-N-benzylidenetobramycin which is used without further purification in the procedure of Example 2.

2. In a manner similar to that described in Example 1D(1), treat each of the 1,3,2,6,3"-penta-N- benzylidene-3,4-dideoxy-kanamycin B and 1,3,2'-tri- N-benzylidene-3",4"-N,O-benzylidene-gentamicin X with triphenylmethyl chloride in dry pyridine followed by treatment of the resultant O-triphenylmethyl ether derivatives with methanesulfonyl chloride in pyridine to obtain 2"-Omethanesulfonyl-6"-O- triphenylmethyl-1,3,2 ,6 ,3 -penta-N- benzylidene- 3,4-dideoxykanamicin B and 2"-O-methanesulfonyl- 6'-O-triphenylmethyl-1 ,3 ,2-tri-N-benzylidene-3 ,4 N,O-benzylidene gentamicin X respectively.

E. 2 '-O-p-toluenesulfonyl-N- benzylideneaminoglycosides In the procedures of Examples 1A, 1B, 1C, and ID, by substituting an equivalent quantity of ptoluenesulfonyl chloride for methanesulfonyl chloride, there is obtained the corresponding 2"-O-ptoluenesulfonyl-per-N-benzylideneaminoglycoside.

F. 2 ',6'-Di-O,N-p-toluenesulfonyl- 1 ,3 ,2 -tri-N- benzylidene 3" ,4" -N ,O-benzylidenegentamicin C Dissolve 1 3 2 -tri-N-benzylidene-3,4"-N,O-benzylidene-gentamicin C (1 g.) in dry pyridine (75 ml.). Distill the pyridine in vacuo, then repeat this procedure twice more with 75 ml. portions of dried pyridine to thoroughly dry the N-benzylidene derivative. Dissolve the dried N- benzylidene derivative in 35 ml. of dry pyridine, add 0.88 g. of p-toluene-sulfonyl chloride (2.2 moles per mole of gentamicin C and allow the reaction mixture to stand at room temperature 3 hours. Add 50 ml. of methanol and evaporate the filtrate in vacuo to a residue comprising 2",6-di-O.N-p-toluencsulfonyl-1,3.2'-

. 20 tri-N-benzylidene-3",4"-N,O-benzylidenegentamicin C,. This material can be used without further purification in the next step.

EXAMPLE 2 2"-deoxy-3"-desamino (or desmethylamino)-2,3"-epimino (or N-methylepimino)-aminoglycosides A. 2"-deoxy-3"-desmethylamino-2",3"-N- methylepiminogentamicin C The starting compound of this example is the 2"-O- methyanesulfonyl-l ,3,2,6-tetra-N-benzylidene- 3",4"-N,O-benzylidene-gentamicin C prepared from 0.5 of 1,3,2',6'-tetra-N- benzylidene-3",4"-N,O-benzy'lidenegentamicin C as described in Preparation 1A(1).

Dissolve the foregoing 2"-O-methanesulfonyl-per-N-' benzylidenegentamicin C in 15 ml. of methanol, add 1.5 ml. of 0. IN hydrochloric acid and stir at room temperature for 6 hours. Dilute the solution with 15 ml. of water and add 0.1N hydrochloric acid until the pH of the reaction mixture is 4.8 (about 8.5 ml. of 0.1N hydrochloric acid are usually added). Stir the acidic reaction mixture at room temperature for 16 hours then extract the solution with 15 ml. of ether and discard the ether extracts. Evaporate the aqueous layer to a residue comprising the hydrochloride of 2"-deoxy-3"- desmethylamino-Z,3"-N-methyl-epiminogentamicin C Purify by chromatography over silica gel eluting with the lower phase of a 2:111 mixture of chlorofrommethanol-15 percent ammonium hydroxide. Assay the eluate fractions by thin layer chromatography and combine the like appropriate fractions. Evaporate the combined eluates to a residue comprising purified 2"- deoxy-3"-desmethylamino-2",3"-N-methylepiminogentamicin C exhibiting the following data: nuclear magnetic resonance (60 MH CDCl 51.05 (doublet, 3H, J=6.5HZ, CH-CH 1.27 (singlet, 3H, C-CH 82.42 (singlet, 3H, NCH 5.08 (doublet, 2J=3.75Hz, anomeric proton), 65.24 (singlet, 1H, anomeric proton); mass spectral peaks at m/ 446 ([M-1-1]+), 333, 332, 316, 314, 305, 304, 286, 287

(pseudodisaccharide ions), 143, 142 (monosaccaride ions), 191, 173, 163, 145 (2-deoxystreptamine ions). In the above procedure in place of the 2-O- methanesulfonyl starting compound there may be used the corresponding 2"-O-p-toluenesulfonyl ester, i.e., 2"-O-p-toluenesulfonyl-1,3,2,6'-tetra-N-benzylidene- 3",4"-N,O-benzylidenegentamicin C and there is obtained the same product, i.e., 2 "-deoxy-3"- desmethylamino-2",3"-N-methylepiminogentamicin C2. B. In similar manner treat each of the 2"-O- methanesulfonyloxazolidine-benzylideneaminoglycosides prepared as described in Examples 18, 1C and 1D with hydrochloric acid in methanol followed by chromatography as described hereinabove to obtain the corresponding 2"- deoxy-3-desamino-2",3"-epiminoaminoglycoside intermediate, i.e.:

2"-deoxy-3"-desmethylamino-Z",3"-N- methylepiminosisomicin,

2"-deoxy-3"-desmethylamino-2,3"-N- methylepiminogentamicin C 2"-deoxy-3"-desmethy1amino-2",3"-N- methylepiminogentamicin C 21 2"-deoxy-3-desmethylamino-2",3"-N- methylepiminoverdamicin,

2"-deoxy-3"-desamino-2",3"-epiminotobramycin, 3',4',2"-trideoxy-3-desamino-2",3"- epiminokanamycin B,

2-deoxy-3-desmethylamino-2",3"-N- methylepimino-Antibiotic Jl-ZO A,

2"-deoxy-3-desmethylamino-2",3"-N- methylepimino-Antibiotic Jl--B,

2-deoxy-3"-desmethylamino-2",3"-N- methylepimino-Antibiotic 6-41 8,

2"-deoxy-3"-desmethylamino-2",3"-N- methylepiminogentamicin X 2"-deoxy-3"-desmethylamino-2",3"-N- methylepiminogentamicin B,

2"-deoxy-3"-desmethylamino-2,3"-N- methylepiminogentamicin B 2-deoxy-3"-desamino-2",3"-epiminotobramycin, 3"-desamino-2",3"-epimino-3,4',2"- trideoxykanamycin B, and

2"-deoxy-3-desmethylamino-2",3"-N- methylepiminogentamicin X respectively.

In the above procedure in place of the 2"-O- methanesulfonylaminoglycoside intermediates there may be used the corresponding 2"-O-ptoluenesulfonylaminoglycosides as starting compounds.

C. 2"-deoxy-3"-desmethylamino-2",3"-N- methylepiminogentamicin C,

l. 6'-N-p-toluenesulfonyl-2"-deoxy-3"- desmethylamino-2",3"-N-methylepiminogentamicin 1 In a manner similar to that described in Examle 2A, treat 6'-N-p-toluenesulfonyl 2"-O-p-toluenesulfonyl- 1,3,2-tri-N-ben2ylidene-3",4"-N,O- benzylidenegentamicin C, with sufficient hydrochloric acid in methanol so that the pH of the reaction mixture is in the range of from 1 to 5. Stir the acidic reaction mixture at room temperature for l6 hours, then isolate and purify the resultant product in a manner similar to Example 2A to obtain 2-deoxy-3"-desmethylamino- 6'-N-p-toluenesulfonyl-2",3"-N- methylepiminogentamicin C 2. Electrochemical reduction toluenesulfonyl group Dissolve 2.45 g. of 2"-deoxy-3"-desmethylamino-6'- N-p-toluenesulfonyl-2,3"-N- methylepiminogentamicin C in 70 ml. of 0.85 M solution of tetramethylammonium chloride in methanol/- water (1:1 Electrolyze the solution with stirring at 1.0 amperes using a mercury cathode and a graphite anode in an RA84 alundum thimble containing water (5 ml.). Electrolyze until thin layer chromatographic analysis of an aliquot of the solution indicates complete disappearance of starting material. Evaporate the solution to a small volume and apply the resultant residue to a column of Amberlite lRC 150 resin (Nl-hl l5 cycle). Wash the column with three volumes of water, then elute with a gradient of ammonium hydroxide (O 0.5N Assay the eluates by thin layer chromatography and evaporate the combined like fractions to a residue comprising 2"-deoxy-3-desmethylamino-2",3"- N-methylepiminogentamicin C.

We claim:

1. In the process for preparing a 2-deoxy-3"- desamino-Z",3"-epimino-4,6-di-(aminoglyeosyl)-2- deoxystreptamine wherein an antibacterially active of the 6'-N-p- 4,6-diaminoglycosyl) -2-deoxystreptamine having a 2"-hydroxyfunction and a 3"-primary or secondary amino function, the primary and secondary amino groups of which are protected by carbobenzyloxy groups, and primary and secondary hydroxyl groups of which are converted to a triphenylmethyl ether of a primary hydroxyl group or a cyclic ketal or acetal of protectable neighboring hydroxyl groups, is treated with a hydrocarbonsulfonyl halide in a tertiary amine, the thereby formed 2"-O-hydrocarbonsulfonyl-per-N- carbobenzyloxy 4,6-di-(aminoglycosyl)-2-de0xystreptamine is treated with hydrogen in the presence of a catalyst, or with'an alkali metal in liquid ammonia, whereby the N-carbobenzyloxy groups are removed; and the resulting 2"-O-hydrocarbonsulfonyl 4,6-di-( aminoglyeosyl)-2-deoxystreptamine is converted to a 2"-deoxy-3-desamino-2",3"-epimino 4,6di- (aminoglycosyl)-2-deoxystreptamine by spontaneous transformation or by heating in a lower alkanol alone or together with an alkali metal salt of said alkanol;

the improvement which comprises protecting primary amino groups and secondary amino groups capable of oxazolidine formation with an aldehyde and a neighboring hydroxyl group in said antibacterial active 4,6-di-(aminoglycosyl)-2-deoxystreptamine by Schiff base-oxazolidine condensation products with an aldehyde devoid of hydroxyl groups; and, after preparation of the 2"-O-hydrocarbonsulfonyl ester thereof, treating the resulting 2"-O-hydrocarbonsulfonyl 4.6-di- (aminoglycosyl)-2-deoxystreptamine having N- protecting-Schiff base -oxazolidine groups with dilute aqueous acid to a pH in the range of from about 1 to about 5, whereby said N-protecting Schiff base-oxazolidine groups are removed.

2. The process of claim 1 including the step of isolating the product thereby formed.

3. The process of claim 1 wherein the N-protecting Schiff base-oxazolidine groups of said 4,6-di- (aminoglycosyl)-2-deoxystreptamine are derived from benzaldehyde, and the dilute aqueous acid treatment of said 2"-O-hydrocarbonsulfonyl ester is carried out with dilute hydrochloric acid.

4. The process of claim 3 including the step of isolating the product thereby formed.

5. The process according to claim l wherein said antibacterially active 4,6-di-(aminoglycosyl)-2-deoxystreptamine having a 2"-hydroxy function and a 3- primary or secondary amino function is a member selected from the group consisting of gentamicin B, gentamicin B gentamicin Cla, gentamicin C gentamicin C2a, gentamicin X and mixtures of the foregoing. sisomicin, verdamicin, robramyein, 3', 4- dideoxykanamycin B, Antibiotic .Il-ZOA, Antibiotic Jl- 2OB and Antibiotic G-4l8.

6. The process of claim 1 wherein said antibacterially active 4,6-di-(aminoglycosyl)-2-deoxystreptamine having a 2"-hydroxyl function and a 3"-primary or secondary amino function is a member selected from the grup consisting of gentamicin C,,,, gentamicin C gentamicin C verdamicin and sisomicin.

7. The process according to claim I wherein said antibacterially activc 4,6-di-(aminoglycosyl)-2-deoxystreptamine having a 2"-hydroxy function and a 3"- primary or secondary amino function is a member sclected from the group consisting of gentamicin B. gentamicin B gentamicin C gentamicin C gentamicin C gentamicin X and mixtures of the foregoing. sisomicin, verdamicin, tobramycin, 3'4,- dideoxykanamycin B, Antibiotic Jl20A, Antibiotic .ll- 20B and Antibiotic G-4l8, wherein the N-protecting Schiff base-oxazolidine groups are derived form benzaldehyde, and wherein the dilute aqueous acid treatment of said 2"-O-hydrocarbonsulfonyl ester is carried out with dilute hydrochloric acid.

8. The process according to claim 1 wherein said antibacterially active i 4,6-di-(aminoglycosyl)-2-deoxystreptamine having a 2"-hydroxy function and a 3"- primary or secondary amino function is a member selected from the group consisting of gentamicin C gentamicin C gentamicin C verdamicin and sisomicin, wherein the N-protecting Schiff base-oxazolidine groups are derived from benzaldehyde, and wherein the dilute aqueous acid treatment of said 2"-O-hydrocarbonsulfonyl ester is carried out with dilute hydrochloric acid,

9. The process of claim 1 wherein said 4,6-di- (aminoglycosyl)-2-deoxystreptamine having a 2"- hydroxy function and a 3"-primary or secondary amino function is gentamicin C wherein the N-protecting- Sehiff base-oxazolidine groups are derived from benzaldehyde, wherein the hydrocarbonsulfonyl halide in a tertiary amine is methanesulfonyl chloride in pyridine, and wherein the dilute aqueous acid treatment is carried out in dilute hydrochloric acid, said process comprising treating l,3,2,6-tetra-N-benzylidene-3", 4"- N,O- benzylidene-gentamicin C with methanesulfonyl chloride in pyridine and treating the thereby formed 2"-O-methanesulfonyl- 1,3,2,,6-tetra-N-benzylidene-3, 4' '-N,O-benzylidene-gentamicin C with dilute hydrochloric acid.

10. The process of claim 9 including the step of isolating the 2"-deoxy-3-desmethylamino-2",3"N- methylepiminogentamicin C thereby formed.

11. The process according to claim 1 wherein the N- protecting-Schiff base-oxazolidine groups of said 4,6- di-(aminoglycosyl)-2-deoxystreptamine are derived from benzaldehyde and the protectable primary and secondary hydroxyl groups of said 4,6-di- (aminoglycosyl)-2-deoxystreptamine are converted to a cyclic acetal with benzaldehyde, said improvement process comprising protecting the primary amino groups and secondary amino groups capable of oxazolidine formation with an aldehyde and a neighboring hydroxyl groups in an antibacterially active 4,6-di- (aminoglycosyl)-2-deoxystreptamine having a 2"- hydroxyl function and a 3"-primary or secondary amino function, by Schiff base-oxazolidine condensation products with benzaldehyde, and converting the protectable primary and secondary hydroxyl groups of said 4,6-di-(aminoglycosyl)-2-deoxystreptamine to cyclic acetals with benzaldehyde, treating said per-N- benzylidene-O-benzylidene 4.6-di-(aniinoglycosyl)-2- deoxystreptamine with a hydrocarbonsulfonyl halide having up to eight carbon atoms in a tertiary amine, treating the resulting O-benzylidene-per-N- benzylidene-Z"-O-hydrocarbonsulfonyl-4.6-di- (aminoglycosyl)-2-deoxystreptamine with dilute aqueous acid to a pH in the range of from about I to about 5, whereby said O-benzylidene acetal groups and said N-benzylidene Schiff base oxazolidine groups are removed.

12. A compound selected from the group consisting of a 2"-O-hydroearbonsulfonyl derivative of the following structural formulae l(a), l(b) and l(c):

M being an aryl radical having up to 8 carbon atoms; X is an organic radical devoid of hydroxyl groups and bonded to the amino and oxygen group through a bivalent carbon radical; th cyclic ketals and cyclic acct-ills thereof devoid of hydroxyl groups; and when R is hydrogen and W',; is hydroxy, the oO-triphenylmcthyl derivatives thereof, and the 6"-O-triphenylmethyl derivatives of compounds of formula He).

13. A compound according to claim l2, formulae [(21) and l(b) wherein M is methyl and X is benzylidenei 14. A compound according to claim 12 formula l(a) wherein M is methyl, X is benzylidene, W and W, are N=X; R and R, are hydrogen, R' is methyl: the sterochemistry at C being R; said compound being I,- 3,2',6-tetra-N-benzylidene-3",4"-N,O-benzylidene- CERTIFICATE OF CORRECTION Patent No. 3, 5 Dated February 5, 1975 Peter J. L. Daniels and Jay Weinstein Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Page 1, Title, "PROCESS FOR PREPARING 2-DEROXY- 5-DESAMINO-2, 5- EPIMINO-AMINOGLYCOSIDES AND INTERMEDIATES USEFUL THEREIN" should read --PROCESS FOR PREPARING 2"-DEOXY- 5"-DESAMINO-2", 5"- EPIMINO-AMINOGLYCOSIDES AND INTERMEDIATES USEFUL THEREIN--- Column l, lines 1 5, the title appears incorrectly as in Page 1. Column 1, lines 5 10, United States Patent Office repeated the last paragraph of the abstract. Column 5, line 65, "gentamicin C A" should read ---gentamicin C Column 5, lines ll 12, "include cylcopropylidene," should read ---include cyclopropylidene,- Column 5, line 65, "-benzylidene-gentamicin Cla" should read -benzylidene-gentamicin C Column 6, line 6, "-benzylidenegentamicin C2a" should read -benzylidene-gentamicin c a Column 6, lines 58 '59, "-l,5,2'-tetra-N- benzylidene-5"-" should read -l,5,2',6'-tetra-N-benzylidene-5", Column 6, line 58, "gentamicin Cla" should read ---gentamicin C a---. Column 6, line 59, "gentamicin 02a," should read ---gentamicin C Column 7, line 31, "analogs therof having" should read ---analogs thereof having--- Column 8, line 15, "-gentamicin Cla" should read ---gentamicin (I Column 8, line 15, "-gentamicin C2," should read -gentamicin C Column 8, line 19, "-gentamicin X2, and" should read -gentamicin X and Column 8, line 59, "-double in" should read -double bond in---. Column ll, lines 6 T, "gentamicin Cla, gentamicin C2, gentamicin C2a" should read ---gentamicin C gentamicin C gentamicin C2a,---. Column 11, line 16, "micin 02a are" should read ---gentamicin 3 a are---. Column 11, line 21, 'C2a being" should read ---C a being---. Column 11, lines 26 28, "gentamicin C2a, as well as the ster eoconfiguration about C 6' of gentamicin C and 0.2a" should read ---gentamicin 0 as well as the stereo- UNITED STATES PATENT OFFICE Page 2' 5 CERTIFICATE OF CORRECTION Patent No. 5,868,560 Dated February 5, 975

Inventor(s) Peter J. L. Daniels and Jay weinstein It is certified that error appears in the aboveidentified patent and that said Letters Patent are hereby corrected as shown below:

configuration about 6-6 of gentamicin C and C Column 15, line +8, "the 22"-O-" should read ---the 2"-O- Column 1 4, lines 16 17, "are gentamicin Cla, gm tamicin C gentamicin C2a," should read ---are gentamicin O gentamicin C gentamicin C Column 15, line 16, "-methyllep'lmino-" should read -methylepimino- Column 15, line 56, "l,5,2',6"-tetra-" should read ---l,5,2',6'-tetra- Column 16, line 16, "-5', +"N,O-" should read -5", +"-N,O., Column 16, line 19, "-5' v'-dideoxy-" should read -5 I d'ldeoxy- Column 16, line 21, "-5", W-N, should read 5", I-"-N,O- Column 16, lines 1LT +8, "1. b h",6"-0- Benz lidon T,5,2' ,6' 5"-benzylidene-" should read (1) 1w 6"-O-Benzylidene-l,5,2' ,6 ,5"-penta-N- Column 17, line 6, "Antibiotic G lu +l8" should read Kntiblotic G- ul8- Column 17, line 2l, "-benzlidene-" should read -benzylidene- Column 17, line 51, "-benzylidene-5" +"-N,0-" should read -benzylidene-5", v'-N,O- Column 18, line 2 1-, 5",u' -N,O-p-" should read LT 3", wl1,o- Column 18, line 37, +",6"-o-" should read --h",6" 0'- Column 18, line 61, "2'-O-methane-sulfonyl-" should read ---2"-O-methanesulfonyl- Column 19, line +7, 2"-O-p-tolu ne sulfonyl N-" should read ---E. 2"-O-p-toluene sulfonyl per-N- Column 20, line 15, "methyanasulfonyL" should read ---methanesulfonyl- Column 20, lines +0 bl, "2J=.75 HZ," should read ---double 2H, J=5.75 Hz,---. Column 21, line 58, "resin (NH ll cycle)." should read ---res'ln (NH cycle).---. Column 22, lines 51 52, "gentamicin Cla, gentamicin C gentamici'n C2a" should read ---gentamicin C gentamicin Cg,

gentamicln C Column 22, line 55, "robramycin," Should read ---tobramycin,--- Column 22, line 60, "grup consisting" should read '---group consisting--.

Column 25, line 29,

Page 5 of 5 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION I Patent: No. 5,868,560 Dated Eebruarv 25 975 Inventor(s) Peter J. L. Daniels and Jay Weinstein It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

"treating l,5,2,6'-tetra-" should read ---trea.ting l,5,2',6'- tetra- Column 23, line +8, "groups in an" should read ---group in an---. Column 21;, line 66, "sterochemistry at" should read ---stereochemistry at---.

Signed and Scaled this seventeenth Day Of February 1976 O [SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN Atresu'ng Officer Commissioner ofPatents and Trademarks 

1. IN THE PROCESS FOR PREPARING A 2'''' DEOXY-3'''' -DESAMINO2'''',3'''' -EPIMINO-4,6-DI-(AMINOGLYCOSYL)-2-DEOXYSTREPTAMMINE WHEREIN AN ANTIBACTERIALLY ACTIVE 4,6-DI (AMINOGLYCOSYL) -25DEOXYSTREPTAMINE HAVING A 2'''' -HYDROXY FUNCTION AND A 3''''PRIMARY OR SECONDARY AMINO FUNCTION, THE PRIMARY AND SECONDARY AMINO GROUPS OF WHICH ARE PROCTED BY CARBOBENZYLOXY GROUPS AND PRIMARY AND SECONDARY HYDROXYL GROUPS OF WHICH ARE CONVERTED TO A TRIPHENYLMETHYL ETHER OFA PRIMARY HYDROXYL GROUP OR ACYCLIC KETAL OR ACETAL OF PROTECTABLE NEIGHBORING HYDROXYL GROUPS, IS TREATED WITH A HYDROCARBONSULFONYL HALIDE IN ATERIARY AMINE, THE THEREBY FORMED 2'''' -OHYDROCARBONSULFONY-2-N-CARBOBENZYLOXY 4,6-DI-( (AMINOGLYCOSYL)-2-DEOXYSTREPTAMINE IS TREATED WITH HYDROGEN IN THE PRESENCE OF A CATALYST, OR WITH AN ALKALI METAL IN LIQUID AMMONIA, WHEREBY THE N-CARBBOBENZYLOZY GROUPS ARE REMOVED; AND THE RESULTING 2'''' -O-HYDROCARBONSULFONYL 4,6-DI-( AMINOGLYCOSYL)-2-DEOXYSTREPTAMINE IS CONVERTED TO A 2''''DEOXY-3''''-DESAMINO-2'''',3''''-EPIMINO 4,6-DI(AMINOGLYCOSYL)2-DEOXYSTREPTAMINE BY SPONTANEOUS TRANSFORMATION OR BY HEATING IN A LOWER ALKANOL ALONE OR TOGETHER WITH AN ALKALI METAL SALT OF SAID ALKANOL; THE IMPROVEMENT WHICH COMPRISES PROTECTING PRIMARY AMINO GROUPS AND SECONDARY AMINO GROUPS CAPABLE OF OXAZOLIDINE FORMATION WITH AN ALDEHYDE AND A NEIGHBORING HYDROXYL GROUP M SAID ANTIBACTERIAL ACTIVE 4,6-DI(AMINOGLYCOSYL)-2-DEOXYSTREPTAMINE BY SCHIFF BASEOXAZOLIDINE CONDENSATION PRODUCTS WITH AN ALDEHYDE DEVOID OF HYDROXYL GROUPS; AND, AFTER PREPARATION OF THE 2''''-O-HYDROCARBONSULFONYL ESTER THEREOF, TREATING THE RESULTING 2''''-O-HYDROCARBONSULFONYL 4,6-DI(AMINOGLYCOSYL)-2- DEOXYSTREPTAMINE HAVING NPROCTECTING-SCHIFF BASE -OXAZOLIDINE GROUPS WITH DILUTE AQUEOUS ACID TO A PH IN THE RANGE OF FROM ABOUT 1 TO ABOUT 5, WHEREBY SAID N-PROTECTING SCHIFF BASEOXAZOLIDINE GROUPS ARE REMOVED.
 2. The process of claim 1 including the step of isolating the product thereby formed.
 3. The process of claim 1 wherein the N-protecting Schiff base-oxazolidine groups of said 4,6-di-(aminoglycosyl)-2-deoxystreptamine are derived from benzaldehyde, and the dilute aqueous acid treatment of said 2''''-O-hydrocarbonsulfonyl ester is carried out with dilute hydrochloric acid.
 4. The process of claim 3 including the step of isolating the product thereby formed.
 5. The process according to claim 1 wherein said antibacterially active 4,6-di-(aminoglycosyl)-2-deoxystreptamine having a 2''''-hydroxy function and a 3''''-primary or secondary amino function is a member selected from the group consisting of gentamicin B, gentamicin B1 , gentamicin C1a, gentamicin C2, gentamicin C2a, gentamicin X2 and mixtures of the foregoing, sisomicin, verdamicin, robramycin, 3'', 4''-dideoxykanamycin B, Antibiotic JI-20A, Antibiotic JI-20B and Antibiotic G-418.
 6. The process of claim 1 wherein said antibacterially active 4, 6-di-(aminoglycosyl)-2-deoxystreptamine having a 2''''-hydroxyl function and a 3''''-primary or secondary amino function is a member selected from the grup consisting of genTamicin C1a, gentamicin C2, gentamicin C2a, verdamicin and sisomicin.
 7. The process according to claim 1 wherein said antibacterially active 4,6-di-(aminoglycosyl)-2-deoxystreptamine having a 2''''-hydroxy function and a 3''''-primary or secondary amino function is a member selected from the group consisting of gentamicin B, gentamicin B1, gentamicin C1a, gentamicin C2, gentamicin C2a, gentamicin X2 and mixtures of the foregoing, sisomicin, verdamicin, tobramycin, 3''4,''-dideoxykanamycin B, Antibiotic JI-20A, Antibiotic JI-20B and Antibiotic G-418, wherein the N-protecting Schiff base-oxazolidine groups are derived form benzaldehyde, and wherein the dilute aqueous acid treatment of said 2''''-O-hydrocarbonsulfonyl ester is carried out with dilute hydrochloric acid.
 8. The process according to claim 1 wherein said antibacterially active 4,6-di-(aminoglycosyl)-2-deoxystreptamine having a 2''''-hydroxy function and a 3''''-primary or secondary amino function is a member selected from the group consisting of gentamicin C1a , gentamicin C2 , gentamicin C2a, verdamicin and sisomicin, wherein the N-protecting -Schiff base-oxazolidine groups are derived from benzaldehyde, and wherein the dilute aqueous acid treatment of said 2''''-O-hydrocarbonsulfonyl ester is carried out with dilute hydrochloric acid.
 9. The process of claim 1 wherein said 4,6-di-(aminoglycosyl)-2-deoxystreptamine having a 2''''-hydroxy function and a 3''''-primary or secondary amino function is gentamicin C2 , wherein the N-protecting-Schiff base-oxazolidine groups are derived from benzaldehyde, wherein the hydrocarbonsulfonyl halide in a tertiary amine is methanesulfonyl chloride in pyridine, and wherein the dilute aqueous acid treatment is carried out in dilute hydrochloric acid, said process comprising treating 1,3,2, 6''-tetra-N-benzylidene-3'''', 4''''-N,O- benzylidene-gentamicin C2 with methanesulfonyl chloride in pyridine and treating the thereby formed 2''''-O-methanesulfonyl-1,3,2,'',6''-tetra-N-benzylidene-3'''', 4''''-N,O-benzylidene-gentamicin C2 with dilute hydrochloric acid.
 10. The process of claim 9 including the step of isolating the 2''''-deoxy-3''''-desmethylamino-2'''',3''''-N-methylepiminogentamicin C2 thereby formed.
 11. The process according to claim 1 wherein the N-protecting-Schiff base-oxazolidine groups of said 4,6-di-(aminoglycosyl)-2-deoxystreptamine are derived from benzaldehyde and the protectable primary and secondary hydroxyl groups of said 4,6-di-(aminoglycosyl)-2-deoxystreptamine are converted to a cyclic acetal with benzaldehyde, said improvement process comprising protecting the primary amino groups and secondary amino groups capable of oxazolidine formation with an aldehyde and a neighboring hydroxyl groups in an antibacterially active 4,6-di-(aminoglycosyl)-2-deoxystreptamine having a 2''''-hydroxyl function and a 3''''-primary or secondary amino function, by Schiff base-oxazolidine condensation products with benzaldehyde, and converting the protectable primary and secondary hydroxyl groups of said 4,6-di-(aminoglycosyl)-2-deoxystreptamine to cyclic acetals with benzaldehyde, treating said per-N-benzylidene-O-benzylidene 4,6-di-(aminoglycosyl)-2-deoxystreptamine with a hydrocarbonsulfonyl halide having up to eight carbon atoms in a tertiary amine, treating the resulting O-benzylidene-per-N-benzylidene-2''''-O-hydrocarbonsulfonyl-4,6-di -(aminoglycosyl)-2-deoxystreptamine with dilute aqueous acid to a pH in the range of from about 1 to about 5, whereby said O-benzylidene acetal groups and said N-benzylidene Schiff base oxazolidine groups are removed.
 12. A compound selected from the group consisting of a 2''''-O-hydrocarbonsulfonyl derivative of the following structural formulae I(a), I(b) and I(c):
 13. A compound according to claim 12, formulae I(a) and I(b) wherein M is methyl and X is benzylidene.
 14. A compound according to claim 12 formula I(a) wherein M is methyl, X is benzylidene, W''2 and W''6 are -N X; R''3 and R''4 are hydrogen, R''5 is methyl; the sterochemistry at C''6 being R; said compound being 1,3,2'',6''-tetra-N-benzylidene-3'''',4''''-N,O-benzylidene-2''''-O -methanesulfonylgentamicin C2. 